if ($sth->selectrow_array('SELECT COUNT(*) FROM '.$Tablename.
'WHERE username = 0x'.unpack('H*',$uname).
' AND password = 0x'.unpack('H*',$pword))) {
 # Successful login
} else {
 # Oops, something failed
}


##</code><code>##

SELECT COUNT(*) FROM users WHERE username = 0x75736572 AND password = 0x313233

##</code><code>##

my ($UserID,$UserState) = $sth->selectrow_array('SELECT ID,State FROM '.$Tablename.
'WHERE username = 0x'.unpack('H*',$uname).
' AND password = 0x'.unpack('H*',$pword));
if ( ! defined($UserID)) {
 # Oops, no UserID means no user with matching username/password was found
} elsif ($UserState eq 'LOCKED') {
 # Oops, this user is not allowed to login
} else {
 # ok, everything right, the user is validated
}